1. A Tale of Two Plants: How Combining WWTP and WTP Improvements in Reidsville is Setting the Stage for the Future
Kevin Irby, P.E.
Kevin Eason, P.E.
2015 Annual Conference
Raleigh, NC

2. A Fresh Start Creates Exciting Opportunities
New Public Works Director 2008
New City Manager
New Council Member
Rate increase
Took back ownership of facilities
New WTP Superintendent

3. A Tale of Two Plants Wastewater Treatment Facility
Aged deteriorated infrastructure (1956)
Highly O&M and chemical intensive
Significant sludge hauling costs
Capital improvements required
Water Treatment Facility
Newer infrastructure
Subject to raw water variability
Significant public visibility and concern
Operational and minor capital improvements required

5. WEEKLY AVERAGES AND LIMITS PLOTTED
Plant has Performed Well with Respect to CBOD, TSS, and Ammonia Effluent Limits
WEEKLY AVERAGES AND LIMITS PLOTTED

6. Areas of Evaluation/Optimization at the WWTP
Nutrient Removal
Biosolids Handling & Disposal
Chronic Effluent Toxicity
Foam Mitigation and Scum Handling
Electrical Power Distribution System
Several Basins had been “repurposed” over the years

7. WWTP Electrical System Issues
Voltage stability - dimming lights when starting equipment
Downtime due to breaker trips
Service is currently at maxed out
Code & safety issues
NEC code violations – cables undersized
Aged equipment – in poor condition
Reliability – single point of failure
Revise graphic to match numbers in Final Report
Electrical improvements required concurrent with solids handling improvements

8. BNR Used For T-P compliance Evaluating Impacts of BNR
Sidestreams contribute to upset of nitrification due to aeration capacity
Filter backwash
Gravity thickener effluent
Sludge Holding Tank Supernatant
RAS discharge location
Insufficient Mixing in Anaerobic/Anoxic Zone
Anaerobic/Anoxic Zone not baffled

9. Sludge Hauling Historically Has Been A Substantial Cost to Reidsville
Contract hauling and land apply
Over $670,000 was spent for sludge hauling in 2011
13,400,000 gallons hauled
Peak year was 2008: over $700,000
9,600,000 gallons hauled (required to haul further distances)
Approximately $5MM since 2006

10. Sludge Hauling Costs are Related to the Concentration of Sludge
~$130,000/yr savings

11. Overview of WWTP Improvements
Solids Processing Improvements
New Solids Thickening
New Solids Dewatering
Additional Aerobic Digester Capacity
New Dewatered Cake Storage
PAC Addition Improvements
Upgrades to Electrical Service and Distribution
Operations Building Roof Replacement
Repaving Plant Roads

12. Recommended Thickening and Dewatering Option

13. Rotary Drum Thickener and Screw Press
~0.5% to ~3.5% (2 units)
~3.5% to ~20% (1 unit)

14. WWTP Recommended Site Plan

15. WTP Improvements Project
ADD WTP
City had experienced a history of discolored water complaints

16. Reidsville WTP Schematic

17. Data Evaluation: Discolored Water Complaints

18. Executive Summary of Water Quality Issues
Widespread – Raw water/WTP is the source
Customer complaints are driven by multiple factors
Varying raw water quality
Manual WTP operations
Start/stop WTP operations
Clearwell residual build-up
Recommendations
Operational improvements
WTP upgrades

19. Implement Multi-barrier Approach to Address Discolored Water Issues
Lake Aeration System Replacement
Raw Water Flow Control
Contact Tank Addition
Chemical Metering Pump Flow Control Improvements
Process Monitoring Upgrades
SCADA System Upgrades

20. WTP Improvements – Proposed Process Flow Diagram
CFE TURBIDIMETER
METERS FOR pH and Cl2

21. WTP Recommended Site Plan

22. Additional Improvements Identified During Preliminary Engineer Review
WWTP
WTP
Replace aeration system in Aeration Basin No. 1
Install new drive on finished water pump
Clean drying beds
Replace filter media
Demolish abandoned trickling filter
Improve raw water metering
Install influent flow metering
Improve finished water metering
SCADA system upgrade
Install new drive on finished water pump (>$17K per trip on existing)

23. Due to Significance of Investment City Opted to Combine into a Single Construction Effort
Estimated $250,000-$300,000 saving on contractors effort
Estimated $50,000 savings on engineers effort
Significant saving of City staff time and effort
Allotted a State zero interest loan of $15,000,000 for WWTP work only

24. How’d We Do? Expected Completion February 2016
Engineers March 2013 OPCC was $17,210,000 for both WWTP and WTP work.
6 Bids were opened on September 30, 2013
Low bid was for $16,476,000
WWTP - $11,948,000
WTP - $4,028,000
Contingency - $500,000
High bid was $18,185,000
Notice to Proceed was issued January 6, 2014
Expected Completion February 2016

25. WWTP Action Photos Blower Air Intakes Rotary drum thickener
Screw Press
Solids Handling Building

26. WWTP Action Photos New Diffuser Grid Inside Aeration Basin
Fiberglass Pipe Inside New Digesters
New Diffuser Grid Inside Aeration Basin

27. WTP Action Shots
Raw water bypass piping
Raw water venture vault

28. Questions?